Macroscopic and microscopic thermodynamic observations in swollen poly(vinyl acetate) networks

Horkay, Ferenc; Hecht, Anne‐Marie; Mallam, Simon; Geissler, Erik; Rennie, Adrian R.

doi:10.1021/ma00010a040

Cited by 162 publications

(145 citation statements)

References 10 publications

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“…Normalizing and correcting for the scattering of the cuvettes was performed with the program Pasidur (32). The incoherent background scattering has been corrected for by following Horkay et al (40). First, the incoherent scattering has been measured using different mixtures of methanol and deuterated methanol, which were treated the same way as the normal samples.…”

Section: Methodsmentioning

confidence: 99%

Osmotic Compressibility of Poly(propylene imine) Dendrimers in Deuterated Methanol

Rietveld

Bedeaux

Smit

2000

Journal of Colloid and Interface Science

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Section: Methodsmentioning

confidence: 99%

Osmotic Compressibility of Poly(propylene imine) Dendrimers in Deuterated Methanol

Rietveld

Bedeaux

Smit

2000

Journal of Colloid and Interface Science

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“…Network inhomogeneities can be thought of as densely crosslinked clusters embedded in a weakly crosslinked (''solution-like'') matrix. The total scattering intensity from polymer gels can usually be described as a sum of thermodynamic and frozen-in components [14][15][16] IðqÞ ¼ I os ðqÞ þ I clus ðqÞ ð 3Þ…”

Section: Scattering From Inhomogeneous Polymer Gelsmentioning

confidence: 99%

Similarities between polyelectrolyte gels and biopolymer solutions

Horkay

Hecht

Geissler

2006

J Polym Sci B Polym Phys

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Small angle neutron scattering (SANS) measurements and osmotic swelling pressure measurements are reported for polyelectrolyte gels and solutions under nearly physiological conditions. A synthetic polymer (sodium-polyacrylate) and three biopolymers (DNA, hyaluronic acid, and polyaspartic acid) are studied. The neutron scattering response of these anionic polyelectrolytes is closely similar, indicating that at larger length scales the organization of the polymer molecules is not significantly affected by the fine details of the molecular architecture (e.g., size and chemical structure of the monomer unit, type of polymer backbone). The results suggest that specific interactions between the polyelectrolyte chains and the surrounding monovalent cations are negligible. It is found that the osmotic compression modulus of these biopolymer solutions determined from the analysis of the SANS response decreases with increasing chain persistence length.

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“…7 or 10. Actually focusing on the upturn scattering, the attempts to determine the static component were performed by the scattering techniques by many researchers in several steps: they found Gaussian function for heterogeneous density of crosslinks 37 or for the heterogeneous concentration fluctuation, 38 stretched exponential function 39 and very recently squared Lorentzian function. 40 Although so many efforts have been made so far, the origin of the upturn scattering is still controversial depending on the types of gels studied.…”

Section: Fig 8 ͑A͒ Temperature-change Of Inverse Forward Scatteringmentioning

confidence: 99%

Concentration fluctuations in polymer gel investigated by neutron scattering: Static inhomogeneity in swollen gel

Koizumi

Monkenbusch²,

Richter³

et al. 2004

The Journal of Chemical Physics

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By using small-angle neutron scattering ͑SANS͒ and neutron spin echo ͑NSE͒, we have quantitatively investigated the static inhomogeneity in poly ͑N-isopropyl acrylamide͒ gel ͑PNIPA͒ in microscopic length scales of 0.015ϽqϽ0.16 A Ϫ1 , where q is a wave number of scattered neutrons. NSE revealed that at lower q(Х0.015 A Ϫ1 ), the concentration fluctuations in the PNIPA gel decays more slowly as compared to the PNIPA solution without crosslinks. According to our scenario that the slower decay found for the PNIPA gel is due to the static inhomogeneity coexisting in the swollen gel, small-angle scattering S(q) obtained by SANS has been quantitatively decomposed into thermal and static scattering components, respectively, S th (q) and S st (q). It was further revealed that ͑i͒ the q-region where S st (q) becomes dominant is closely related to that for the abnormal butterfly scattering under stretching, and ͑ii͒ as the temperature increases toward the temperature for volume phase transition, S st (q) of a squared Lorentzian shape increases more drastically than S th (q) of a Lorentzian shape. These findings were quantitatively understood in the theoretical framework by Panyukov and Rabin ͓Macromolecules 29, 7960 ͑1996͔͒ or by Onuki ͓J. Phys. II. France 2, 45 ͑1992͔͒, taking into account stress-fluctuation coupling under coexistence of the inherent structural heterogeneity in the real gel. We further found that the static inhomogeneity showing S st (q) seems to relate to the necklacelike microstructure, appearing after a shallow quench into the collapsed phase.

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Macroscopic and microscopic thermodynamic observations in swollen poly(vinyl acetate) networks

Cited by 162 publications

References 10 publications

Osmotic Compressibility of Poly(propylene imine) Dendrimers in Deuterated Methanol

Osmotic Compressibility of Poly(propylene imine) Dendrimers in Deuterated Methanol

Similarities between polyelectrolyte gels and biopolymer solutions

Concentration fluctuations in polymer gel investigated by neutron scattering: Static inhomogeneity in swollen gel

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